The range, or Dehesa , is the ideal habitat of the Iberian breed swine. The dehesas are agro-ecosystems that have developed from the previous Mediterranean forest of Quercus (of the oak family) species and have been cleared of shrub to favour grazing and acorn production. The Dehesa occupies a significant part of the region of Extremadura and large tracts of land in the province of Salamanca .

Holm-oak and cork-oak dehesas are one of the best examples of crop-and-livestock-rearing systems in which human activities have respected the natural environment, and it is one of the few models of truly ecological agriculture. However, the special importance behind all this is that free-range Iberian breed swine rearing (as referred to the“ pata negra” breed in local parlance) has to a large extent been responsible for the conservation of -and ecological respect accorded to- the dehesas.